The most common methods for renaturing a protein, such as an aggregate or an inclusion body, mainly involve dilution, chromatography and dialysis. Such three methods have a same principle for refolding a protein, that is, since the protein in an active site is of the lowest energy level of a protein molecule, an internal structure of a peptide chain in a protein to be renatured is rearranged spontaneously at a decreasing concentration of a denaturing agent in a denaturing solution, thereby minimizing the energy level of the protein molecule in the protein gradually, thus the activity of the protein is recovered. However, it is inevitable to avoid the peptide chain from aggregating because of a thermal motion of the protein molecule, which will lead to a failure of protein renaturation. The chromatography method has many disadvantages, such as high requirement, expensive column stuffs, low throughput, strict conditions, complex optimization of the column stuffs, and so on. Although being capable of obtaining a product in a high concentration, the dialysis method is easily to cause precipitation. The dilution method, mostly used in the current research application and production, and being substantially to renature a protein to be renatured by diluting a renaturation solution gradually, is mostly optimized by altering components of the renaturation solution and proportions thereof, the conditions for dilution and so on, so as to improve the renaturation efficiency of the protein, compared to a 10% renaturation yield obtained in the present dilution method. Nevertheless, it is impossible to avoid the sample from being diluted excessively.
Therefore, there is still a need to further improve the existing method for renaturing a protein.